Network operators are increasingly monetizing their infrastructure with services. Services range from mobile line termination, lawful interception, charging, but also application-specific (in-line) services such as Hypertext Transfer Protocol (HTTP) proxies, Transport Control Protocol (TCP) optimizers, firewalls, and Network Address Translation (NAT) functions.
In a service-routed infrastructure used by a network operator, a chain of services can alter traffic between originating nodes and remote, possibly Internet hosted services. All packets to and from the originating node are subjected to one or more of these services.